The vapor bubble interface for nucleate pool boiling of a binary mixture subjects to both concentration gradient and temperature gradient, which give rise to interfacial shear, and may create Marangoni flow. A proposed microwedge model is adopted to demonstrate that, variation of surface tension along microwedge interface would be beneficial for liquid layer merging each other, and consequently, detaching fully grown bubbles from the heated surface even under microgravity. This is in quite good agreement with the experimental observations in the literature. The model can be further extended to explain pool boiling phenomena of binary mixtures at high heat fluxes or even CHF under microgravity.